package internal

// Gamma8 converts 8-bit luminance y according to CIE 1976.
func Gamma8(y byte) byte {
	return gamma[y]
}

// Gamma table according to CIE 1976.
//
//	const max = 255
//
//	for i := 0; i <= max; i++ {
//		var x float64
//		y := 100 * float64(i) / max
//		if y > 8 {
//			x = math.Pow((y+16)/116, 3)
//		} else {
//			x = y / 903.3
//		}
//		fmt.Printf("%d,", int(max*x+0.5))
//	}
//
//emgo:const
var gamma = [256]byte{
	0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3,
	3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 7, 7, 7,
	7, 8, 8, 8, 8, 9, 9, 9, 10, 10, 10, 10, 11, 11, 11, 12, 12, 12, 13, 13, 13,
	14, 14, 15, 15, 15, 16, 16, 17, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22,
	22, 23, 23, 24, 24, 25, 25, 26, 26, 27, 28, 28, 29, 29, 30, 31, 31, 32, 32,
	33, 34, 34, 35, 36, 37, 37, 38, 39, 39, 40, 41, 42, 43, 43, 44, 45, 46, 47,
	47, 48, 49, 50, 51, 52, 53, 54, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64,
	65, 66, 67, 68, 70, 71, 72, 73, 74, 75, 76, 77, 79, 80, 81, 82, 83, 85, 86,
	87, 88, 90, 91, 92, 94, 95, 96, 98, 99, 100, 102, 103, 105, 106, 108, 109,
	110, 112, 113, 115, 116, 118, 120, 121, 123, 124, 126, 128, 129, 131, 132,
	134, 136, 138, 139, 141, 143, 145, 146, 148, 150, 152, 154, 155, 157, 159,
	161, 163, 165, 167, 169, 171, 173, 175, 177, 179, 181, 183, 185, 187, 189,
	191, 193, 196, 198, 200, 202, 204, 207, 209, 211, 214, 216, 218, 220, 223,
	225, 228, 230, 232, 235, 237, 240, 242, 245, 247, 250, 252, 255,
}
